DESCRIPTION: This application will focus on the hypothesis that specific components of 60 Hz EMF exposure, harmonics and transients, might represent a potential health risk to humans and in the present instance, to reproductive outcome. Accordingly, the aim of the application is to evaluate the effects of EMF components (harmonics and transients) as well as time varying field intensities on reproductive outcome using maternal exposure of fetal rats. Two studies will be performed, one to examine the effects of power frequency harmonics, and the other to examine the effects of power frequency transients and time varying field intensities. The endpoints monitored to evaluate EMF exposures for reproductive effects include a panel of traditional endpoints for assessing developmental toxicity such as number of implantation sites, number of aborted/absorbed implantations, mean fetal weight and the like. In addition, the fetuses will be evaluated using a traditional panel of endpoints for detecting developmental anomalies including skeletal as well as gross morphological anomalies of viscera. Selected fetuses will be evaluated for levels of a glial fibrillary acid protein (GFAP), which is a marker for CNS injury.